1. Field
Example embodiments of the inventive concepts relate to semiconductor memory devices, and more particularly, to nonvolatile memory devices and operating methods thereof.
2. Description of the Related Art
Semiconductor memory devices are memory devices that are realized using semiconductor materials such as silicon (Si), germanium (Ge), gallium arsenide (GaAs) and indium phosphide (InP).
Semiconductor memory devices are generally classified into volatile and nonvolatile memory devices. Volatile memory devices are memory devices in which stored data is erased when the power source is shut off. Examples of volatile memory devices include Static Random Access Memory (SRAM), Dynamic Random Access Memory (DRAM), and Synchronous Dynamic Random Access Memory (SDRAM). In contrast, nonvolatile memory devices are memory devices that retain stored data even when the power source is shut off. Examples of the nonvolatile memory devices include Read Only Memory (ROM), Programmable Read Only Memory (PROM), Erasable Programmable Read Only Memory (EPROM), Electrically Erasable Programmable Read Only Memory (EEPROM), flash memory device, phase-change random access memory (PRAM), Magnetoresistive Random Access Memory (MRAM), Resistive Random Access Memory (RRAM) and Ferroelectric Random Access Memory (FRAM). Flash memory devices are largely categorized into NOR and NAND types.